Issues > July/August 2006 (#115) > Science You Can Sink Your Teeth Into: Sealants, Aspartame and Amalgam

Science You Can Sink Your Teeth Into: Sealants, Aspartame and Amalgam

It's summer and with fresh berries in season you can indulge your child's sweet tooth while avoiding high-sugar treats. But for that summer dental checkup, here's the latest research on some rather toothy topics: dental sealants, mercury in fillings and the safety of artificial sweeteners.

Don't Swallow Sealants

Dental sealants, plastic coatings that can protect teeth from cavity-causing bacteria, may release the estrogenic chemical bisphenol A (BPA), which is linked in animal studies to decreased sperm production, early puberty and miscarriage (see GG #114). Recently, BPA was also linked to prostate cancer, according to a study in the June 1, 2006 Journal of Cancer Research. Dentists commonly apply sealants to hard-to-clean molars, using them on 32 percent of U.S. children, according to the Centers for Disease Control and Prevention (CDC).

Some sealants contain BPA and can release it into the body during application, according to a study in the March 2006 Journal of the American Dental Association. Researchers tested 14 volunteers immediately after sealant application and found that patients who received Delton Light Cure (LC) Opaque brand absorbed about 110 micrograms of BPA, 20 times that absorbed by recipients of another brand, Helioseal F (5.5 micrograms). Delton Light Cure (LC) leached amounts similar to those that caused developmental toxicity in rodent studies and, at 42.8 parts per billion (ppb), are higher than the highest amount found in canned food, 38 ppb (see "The Bisphenol-A Debate," GG #114).

"We believe this is because there is incomplete curing of the sealant," says Dana Barr, Ph.D., a research chemist at the CDC. "If the patient doesn't spit it out, he or she will likely swallow it." The American Dental Association's position on BPA states, "there is no evidence to suggest a link between any adverse health condition and BPA leached out of dental sealants."

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